1. Field of the Invention
The invention relates to a bismaleimide-triazine resin and a production method thereof and in particular, to a series of novel BT resins prepared by reacting a novel bismaleimide monomer with various aromatic cyanate esters.
2. Description of the prior art
There are not so many types of BT resins known in the art and those are made predominantly by combining diphenylmethane bismaleimide with bisphenol A cyanate resin in various mole ratios. The present invention consists of preparing a series of novel BT resins by using novel bismaleimides with various aromatic cyanate esters.
U.S. Pat. No. 4,110,364 (Mitsubishi, Japan, 1978 ), disclosed a BT resin synthesized from bismaleimide and cyanate ester. As shown in FIG. 1, cyanate ester itself can be cyclotrimerized in to a triazine structure (10), or it can be copolymerized with a maleimide to form a pyrimidine structure(11), where R1 in FIG. 1 is as shown in FIG. 2, R2 is as shown in FIG. 3, and where R in FIG. 2 and 3 may be H, lower alkyl group (C1-C7 ), cycloalkyl(C4-C7 ), phenyl and the like, and m=0-4.
BT resin has excellent elevated temperature characteristics, solvent resistance, low water absorption, and low dielectric constant. Such resin compositions can be blended with other thermosetting resins and other reactive diluents such as o-diallyl phthalate, triallyl cyanurate or triallyl isocyanurate, to modify such BT resin.
Many BT resins known in the art are made predominantly from diphenylmethane bismaleimide and bisphenol A cyanate resin in various proportions. BT resins comprise solid, liquid and solution types, are applicable in a variety of processing uses such as laminating, preformed insulating sheet structural materials, coating, filling and the like, and can be used in multi-layer printed circuit boards and as encapsulants.